The present invention relates to a suction pump for draining body fluids from body cavities, the suction pump comprising a bottom portion and a domed resilient pump body having a substantially smooth inner surface, the pump body being connected to the bottom portion along its rim and forming a pumping chamber between the bottom portion and pump body, which suction pump further comprises an inlet valve and an outlet valve, the resilient pump body being resiliently deformable by manual action from its domed configuration towards the bottom portion for the provision of the pressure stroke of the suction pump and due to its elasticity returning to its domed configuration when relieved for the provision of the suction stroke of the pump.
A pump of the type mentioned above is disclosed in EP patent application No. 87307362.1 (publication No. 0270205). The domed pump body of the noted pump has a flat top which may be supported along its inner surface by means of two sets of intersecting ridges and the bottom portion is flat and may be provided with a set of upwardly extending ridges. In its deformed state the bottom and the inner surface of the pump body are spaced, and hence the pump has a large pump clearance volume, which means that only a relatively small part of the pump chamber is used in the pumping operation. The prior art pump is implantable and serves to transport body fluid from one cavity of the body into another when activated. Furthermore, the ridges of the pump body, if provided, serve to quickly return the pump body to its starting position. Similar pumps having an internally smooth domed pump body and a flat bottom portion are disclosed in GB 1,146,413 and GB 1,173,071.